This invention relates to inspection of parts, and more particularly to comparing a physical part to a computer model of the part.
When designing, developing, or optimizing a product, such as a part for a vehicle, it is common to create a computer model of the part. In some cases, computer-aided design (“CAD”) software tools are used to create a computer model. A computer model of a part typically has a plurality of surfaces. For example, a CAD model of a cube would have six planar surfaces. However, in more a complex CAD model, such as a casting for a turbine engine, there will be many more surfaces, and it is likely that not all surfaces will be planar. In one example, a designer operating CAD software and the CAD software itself determine what constitutes a surface within a computer model. A typical CAD model may comprise hundreds or even thousands of individual surfaces.
Once a part is actually created, it is desirable to compare the part to an associated computer model of the part to verify that the part has been created accurately as part of an end of line quality control process. In the past this was achieved through mechanical inspection via a surface plate using a height gage, rotary tables, and handheld inspection tools. However, an example part may have hundreds or thousands of surfaces, and mechanical inspection is slow and does not provide sufficient data to obtain accurate measurements.
More recently, scanners have been used to scan a part with a laser to obtain detailed coordinate data for a plurality of points on the part. Some scanners are able to obtain coordinate data for up to 400,000 points per second. Software may be used to compare the coordinate data to an associated computer model of the part. Comparison data may then be reported in a visual display. Existing software reports comparison data for an entire area of a part. This is undesirable because an area of a part may have hundreds of different surfaces that are being reported simultaneously. When comparison data for so many surfaces is displayed simultaneously, isolating and diagnosing problematic surfaces becomes very difficult. There is a need for an improved system for part inspection.